The present invention relates to the field of paper manufacturing. More particularly, the present invention relates to the manufacture of absorbent tissue products such as bath tissue, facial tissue, napkins, towels, wipers, and the like. Specifically, the present invention relates to improved papermaking belts used to manufacture absorbent tissue products having background regions optionally bordered by decorative elements, methods of tissue manufacture, methods of fabric manufacture, and the actual tissue products produced thereby.
In the manufacture of tissue products, particularly absorbent tissue products, there is a continuing need to improve the physical properties and final product appearance. It is generally known in the manufacture of tissue products that there is an opportunity to mold a partially dewatered cellulosic web on a papermaking belt specifically designed to enhance the finished paper product's physical properties. Such molding can be applied by fabrics in an uncreped through-air dried process as disclosed in U.S. Pat. No. 5,672,248 or in a wet pressed tissue manufacturing process as disclosed U.S. Pat. No. 4,637,859. Wet molding typically imparts desirable physical properties independent of whether the tissue web is subsequently creped, or an uncreped tissue product is produced.
However, absorbent tissue products are frequently embossed in a subsequent operation after their manufacture on the paper machine, while the dried tissue web has a low moisture content, to impart consumer preferred visually appealing textures or decorative lines. Thus, absorbent tissue products having both desirable physical properties and pleasing visual appearances often require two manufacturing steps on two separate machines. Hence, there is a need for a single step paper manufacturing process that can provide the desired visual appearance and product properties. There is also a need to develop a paper manufacturing process that not only imparts visually discernable pattern and product properties, but which does not affect machine efficiency and productivity.
Previous attempts to combine the above needs, such as those disclosed in International Application Nos. PCT/US13/72220, PCT/US13/72231 and PCT/US13/72238 have utilized through-air drying fabrics having a pattern extruded as a line element onto the fabric. The extruded line element may form either discrete or continuous patterns. While such a method can produce textures, extrusion techniques are limited in the types of lines that may be formed resulting in reduced permeability of the through-air drying fabric. The reduced permeability in-turn decreases drying efficiency and negatively affects tissue machine efficiency and productivity.
Additionally, traditional papermaking belts 10 are formed to be endless belts by the joining of a seam 12, as illustrated in FIG. 1. The seam 12 can be joined in a cross-direction CD to the papermaking belt 10. Seams 12 can provide a source of breakdown for the papermaking belt 10 over time, ultimately leading to the need for replacement of the papermaking belt 10. In fact, such limitations due to seams 12 can prevent the commercialization of otherwise desirable papermaking products due to the reduced longevity of a papermaking belt 10.
Seams 12 in a belt 10 can also impart undesirable or inconsistent characteristics to the tissue web. The seam 12 can provide varying characteristics in air transfer/permeability of the papermaking belt 10 in comparison to other areas of the papermaking belt 10 not at the seam 12, which can lead to inconsistent characteristics for the tissue web that contacts or is associated with the seam 12. In addition, seams 12 can provide difficulty in transferring a pattern from the belt 10 to the tissue web leading to bad aesthetics of the web, wet spots on the web, and/or sheet breaks.
As such, there remains a need for articles of manufacture and methods of producing tissue products having visually discernable patterns with improved physical properties without losses to tissue machine efficiency and productivity.